A Novel Methodology for Gain Enhancement of the Fabry-Pérot Antenna

A significant problem that is encountered with the traditional Fabry-Pérot cavity (FPC) antenna is the nonuniform phase distribution inside the cavity, which adversely affects the radiation characteristics of the antenna. In this paper, a novel methodology is proposed to further enhance the gain of the FPC antenna. A metasurface with a controllable reflection phase is designed to correct the phase distribution to a nearly uniform distribution, thereby enhancing the antenna gain. The unit cell of the metasurface is a simple substrate with two patches. The top layer patch is sufficiently large to provide high reflectivity, whereas the bottom layer patch has a variable size to tune the reflection phase of the unit cell. Using the proposed formula, a metasurface with a reflection phase correction is designed. The antenna gain is further enhanced, and high aperture efficiency is obtained. A prototype antenna is fabricated and measured. The measured results are in very good agreement with the simulated results. The measured results show that the antenna has a 3 dB gain bandwidth of 4% (9.8 GHz- 10.2 GHz). On average, a 2 dB gain enhancement is obtained Compare to the reference antenna. The maximum gain of the antenna reaches 19.7 dBi at 10 GHz with an aperture efficiency of 82.5%.